Ball, John (1927). "Problems of the Libyan Desert". The Geographical Journal. 70 (1): 21–38. doi:10.2307/1781881. JSTOR1781881.
Ball, John (1933). "The Qattara Depression of the Libyan Desert and the Possibility of Its Utilization for Power-Production". The Geographical Journal. 82 (4): 289–314. doi:10.2307/1785898. ISSN0016-7398. JSTOR1785898.
Badescu, Viorel; Cathcart, Richard B., eds. (2011). Macro-engineering Seawater in Unique Environments. Environmental Science and Engineering. Berlin, Heidelberg: Springer Berlin Heidelberg. doi:10.1007/978-3-642-14779-1. ISBN9783642147784.
Ball, John (1927). "Problems of the Libyan Desert". The Geographical Journal. 70 (1): 21–38. doi:10.2307/1781881. JSTOR1781881.
Ball, John (1933). "The Qattara Depression of the Libyan Desert and the Possibility of Its Utilization for Power-Production". The Geographical Journal. 82 (4): 289–314. doi:10.2307/1785898. ISSN0016-7398. JSTOR1785898.
Ball, John (1933). "The Qattara Depression of the Libyan Desert and the Possibility of Its Utilization for Power-Production". The Geographical Journal. 82 (4): 289–314. doi:10.2307/1785898. ISSN0016-7398. JSTOR1785898.